| Message ID | 20181218060921.11314-1-ike.pan@canonical.com |
|---|---|
| State | New |
| Headers | show |
| Series | Backport race condition fix | expand |
On 12/18/18 7:09 AM, Ike Panhc wrote: > From: Jason Yan <yanaijie@huawei.com> > > Buglink: http://bugs.launchpad.net/bugs/1808912 > > When the lldd is processing the complete sas task in interrupt and set the > task stat as SAS_TASK_STATE_DONE, the smp timeout timer is able to be > triggered at the same time. And smp_task_timedout() will complete the task > wheter the SAS_TASK_STATE_DONE is set or not. Then the sas task may freed > before lldd end the interrupt process. Thus a use-after-free will happen. > > Fix this by calling the complete() only when SAS_TASK_STATE_DONE is not > set. And remove the check of the return value of the del_timer(). Once the > LLDD sets DONE, it must call task->done(), which will call > smp_task_done()->complete() and the task will be completed and freed > correctly. > > Reported-by: chenxiang <chenxiang66@hisilicon.com> > Signed-off-by: Jason Yan <yanaijie@huawei.com> > CC: John Garry <john.garry@huawei.com> > CC: Johannes Thumshirn <jthumshirn@suse.de> > CC: Ewan Milne <emilne@redhat.com> > CC: Christoph Hellwig <hch@lst.de> > CC: Tomas Henzl <thenzl@redhat.com> > CC: Dan Williams <dan.j.williams@intel.com> > CC: Hannes Reinecke <hare@suse.com> > Reviewed-by: Hannes Reinecke <hare@suse.com> > Reviewed-by: John Garry <john.garry@huawei.com> > Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> > Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> > (cherry picked from commit b90cd6f2b905905fb42671009dc0e27c310a16ae) > Signed-off-by: Ike Panhc <ike.pan@canonical.com> Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com> > --- > drivers/scsi/libsas/sas_expander.c | 9 ++++----- > 1 file changed, 4 insertions(+), 5 deletions(-) > > diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c > index 6a4f8198b78e..0ebed2a86b97 100644 > --- a/drivers/scsi/libsas/sas_expander.c > +++ b/drivers/scsi/libsas/sas_expander.c > @@ -48,17 +48,16 @@ static void smp_task_timedout(struct timer_list *t) > unsigned long flags; > > spin_lock_irqsave(&task->task_state_lock, flags); > - if (!(task->task_state_flags & SAS_TASK_STATE_DONE)) > + if (!(task->task_state_flags & SAS_TASK_STATE_DONE)) { > task->task_state_flags |= SAS_TASK_STATE_ABORTED; > + complete(&task->slow_task->completion); > + } > spin_unlock_irqrestore(&task->task_state_lock, flags); > - > - complete(&task->slow_task->completion); > } > > static void smp_task_done(struct sas_task *task) > { > - if (!del_timer(&task->slow_task->timer)) > - return; > + del_timer(&task->slow_task->timer); > complete(&task->slow_task->completion); > } >
diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c index 6a4f8198b78e..0ebed2a86b97 100644 --- a/drivers/scsi/libsas/sas_expander.c +++ b/drivers/scsi/libsas/sas_expander.c @@ -48,17 +48,16 @@ static void smp_task_timedout(struct timer_list *t) unsigned long flags; spin_lock_irqsave(&task->task_state_lock, flags); - if (!(task->task_state_flags & SAS_TASK_STATE_DONE)) + if (!(task->task_state_flags & SAS_TASK_STATE_DONE)) { task->task_state_flags |= SAS_TASK_STATE_ABORTED; + complete(&task->slow_task->completion); + } spin_unlock_irqrestore(&task->task_state_lock, flags); - - complete(&task->slow_task->completion); } static void smp_task_done(struct sas_task *task) { - if (!del_timer(&task->slow_task->timer)) - return; + del_timer(&task->slow_task->timer); complete(&task->slow_task->completion); }